1. Field of Invention
The invention relates to a backrest of a chair, stool, or the like and more particularly to two fastening mechanisms for flexibly securing a J-bar to chair backrest and chair headrest respectively with improved characteristics including lessening the effect of jarring and effectively relieving stress of the spine of a seat person and thus providing an increased degree of comfort to the person.
2. Description of Related Art
Backrest is an important component of a chair since a well designed backrest can provide a degree of comfort to a seat person. There have been numerous suggestions in prior patents for chair backrest. For example, U.S. Pat. No. 5,195,804 discloses a chair having two oval shaped shells each concave to vertical and convex to horizontal. Also, PCT Patent Application WO91/18539 discloses a backrest. Both patents aim at effectively relieving stress of the spine of a seat person.
However, the devices shown in the prior art are complex in structure, are subject to malfunction, and are cost ineffective. Moreover, so far as the inventor is aware, the conventional devices have had no market acceptance. Thus, continuing improvements in the exploitation of chair backrest are constantly being sought.